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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd02e80cee1a0d73ca316d9e187b94f3b1a3df3c701c0856a389e6d6327b7ad23' 
  AND token = 'E6jlML337grk3awZ9TaqaAxgLHGrKpcK/WpjnB3a0QE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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