SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e73f31d64dd309cfedbc4b41cfebf44da34aed025bac56eeb45cbc85daf37c67' 
  AND token = '+0yX+21DOhkHt+ohoCLEJ4Hb0hfLLJ6gWEFqRshoVbE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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