SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd765e0df36d49dda3a0cd6000551518c682a279a477dc93c070647a6fc2f800' 
  AND token = '3+h73RgDdh75xvG5qiF2BGhdwIibECxW5mqYct3f6kE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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