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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae51e55ee55e52b1eb8afef9e8b38b797c3bdc32a608cbb370ee110436f79c53' 
  AND token = '1sL+GWWQXw2bUF2dQ0O1MdqsgiUMOo0Rqpc8CpKOboA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}