SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dd4d3e641ee6e90ec1c2d2c64245dbc5b52c767f2b99d08f59b769e1cbab3709' 
  AND token = 'QQy1QOQ7HCB1RO8cZApk6LBAhC5dweOGinT6dIOpRqk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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