SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'bf603c36313665b63d2ce870a53a7444ccaad1e189e7a24fe8222977dad5c6f6' 
  AND token = 'gcW9HoXbPlt94aN/M9Gnz2+Re3GQZVNRxeIDplAnoh8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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