SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '439b7f99fbfe38b97515e7f82d59c99fb2cf0374c677a866489639b5eea8f934' 
  AND token = '7lUve47k64I/XEkMciSM6DNDr8ay933VyDsn1w6PVW4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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