SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e83660c347c65ec5d42ee7373dd5bb6084dbe9980d04a65f95c4adaa0274a402' 
  AND token = 'OHR8pJChG2+5VyMl5/6YYeXZit0Ihpd2QXiwAttAQR0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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