SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73896a67bd933ac2913cf2cbcb7a81467b1459395c5bdd22c1317d8683ca5b23' 
  AND token = 'SbDq47kTTqoOIXKzXCnV+rPT4oBhub1Q+QCaEFdlEMg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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