SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd56fc9404a3fe95aae2f48c22486b161c16ac9b93b2ce5115a41985bd333b1ca' 
  AND token = 'gHJPuZPFXu1sq7A36bWYz7jKR0siF/hiCfSq+DjwDNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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