SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '524d15d180d8e486e177f6980465e90d8bc23d78b6650310d5113d4f1292e903' 
  AND token = 'PamxRIxYqboZt6VR2pdmmJZkSthk9kSDgYAKwLsGhrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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