SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fc813713aa0c57d5b22bf025f00143a54079d2245352b7b346e3592acd6508d' 
  AND token = 'SfRldw6J0UJNw+1avsXEwzJguJvY/m8d2KDsWIj+Wkw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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