SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3ae6799c444747b002a02e872d80b807db8f095e54fc555226bf38a64e36ebd' 
  AND token = 'VFmqKUL2NPoFGW4zv8rgmlO8njJ1PS1eK4sG75Ul+PU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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