SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '53b547959ddca600a3d2407e5aa71445dd797b847c9c3355962db989816da1ea' 
  AND token = '09q/1ALce2TgrfwIZyeWl15jS1Ty6iMenksVa/dvhkY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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