SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4b9c15e65d67ec6a36f429c6dbb2cfe9ef79f1abbcea494506f1bf4ed96990fe' 
  AND token = 'lbByEYShQsVJv0Hwyo1rU3yoS1jDSSGmz2dwrzoi2UM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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