SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c7b7efaf3f297f8daadd46ebba0052eb6036b504e2ce1be3625ba703e1e96f87' 
  AND token = 'PYN6deOK51NwujOPboB1F/B6O1TF+wsxGnAl2LW7DXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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