SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7875beda6849b7e7e66ad4ff5412ebbbfcd8cfe889e039fcaab55597d3717b5c' 
  AND token = 'jhCIcxRXum1IS0KzV6c4ik3Rjd5zCfkzrAqrooPpm5I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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