SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c26f11d72035ee5e80e6e6528fd640d4bab017453012335276b8d3602c17198e' 
  AND token = 'kfkprX4naUlFoVzhJgvcvXeojahBwA+LfSnnMFvo628=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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