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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4e2b5c62b0a123d7b9ef94ceaf75b7a3bcd9a4ab4d22cbbbdba958e5344dfcd' 
  AND token = 'xdGMvwayXhhlW4skGffsLr1yosKQff69UXQsX8uBrnk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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