SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5fadafbe088627be5e9582af7a23c62881783fd89d587e302106e4d3af9ee8f' 
  AND token = 'IyIuZMxubXxXxVqQuztPHqz9NFCcDy83zz7q/pXOs7c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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