SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ef792bf785cdbf4e5303b0ea0252a671099164153cad70043e0efc7ce75dfa46' 
  AND token = '18UIXIth8tJ6/A+usJrw6BDvzsQ5O5EBiq1L8DaoZDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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