SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1adc021d67f87c65ecfa437c0345e64ba6a5fd98bcd8daf026853656de15db3c' 
  AND token = 'UasqwW3gBietL1opXYIMAG4O+ELtl2jyzDTMbO727es=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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