SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92424469d05c711de6b4f5f90281549f36a1576f60004092065a129d9baf996b' 
  AND token = 'UwPQ3NWkxqF6+ATQjwy8yWNIUGOGsHvvmCB7wMnGFZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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