SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6da31ea6df9c236cb1dd5d677b4810c178ba42661328f4746163006ea107a49b' 
  AND token = '55iLjYyUhKBNM3jrM3M5p4vIuqT+j+TeVm+mJdzPeB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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