SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '479f75cb1aabd33dd3eed385e2b4fdba77432321a60c77b12bbd36f46127a1dc' 
  AND token = '6XfrWydyqRNiDnfEhH28IqZR76jTO/OhlhTsaJRTcn4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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