SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfa8eb96b2aecfbadc37b674792c82003dba3de08058220ef926bfd2419d74f5' 
  AND token = '6dHYqdMD3QQ2AH2JZzgzpHaK/Q5JoDVY9Jkpx3+hz/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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