SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad22313f311dbabf0f8cdd1f48c86a504cde1afd1017c241442621ec3ee2d293' 
  AND token = 'pOnPOUI9yNmO1T+wC7ZlNLYYz1nbWN3/ctkld+z2YkQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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