SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0f18458ed5dd66e8c93ad94a84ac2e30dfafdc2897b222df0ba5aec96ee75eb' 
  AND token = 'qag+WMUu/c9Bw8AaJjEmED+DzcrDesWaqOR/KB6y+fQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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