SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4400a0f708134586885ae143e3dfe7c9a4851b7a11a176267fb3905c92c6aebe' 
  AND token = '1bEMGzKw4tiZbJUqTBFlbnDURUtUcTkkwY61sZvSuZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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