SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f43a9ee3726b599ef283f41d4f308bfd931bd55a670c80c9dd9542c07222d55' 
  AND token = 'V3GKQJgtqXa1EsEGOS/OHpJKWvlKnYKgH3Pg8FjGP+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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