SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb39afd906cae009076eb87a557685db5694f80e3a62ea74b91bba5873c627ef' 
  AND token = 'QXKduPq9DTsWAEHwwmLAUOjEKbFB3M7NOUP+tyPRdfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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