SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53734978986d7b5c4a3aebebd8de6f690aadccf8d13108a7b60bbcc39c4dad11' 
  AND token = '17T8+vqrjc8ZjwL1UnpSVmOyHMaQglISWUwFmygTa8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}