SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8de426ad6699e35bd8a5cb5ef9742964b0de4535d5ecb48744a6847f5109e727' 
  AND token = '9PqX+3h7w9xaqAPOJfGbXZGBP1GYJQ5XsYg/K/9/zvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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