SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fc5f74bf37aed591c42484a76fb1fa83520b0f1b1583357ba996afcfcf14042' 
  AND token = '3Ne9zVMFSwQCJh4P5YCy1+lEJr6Os0ZAoBpv/kqHTtY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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