SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '050b99596a597f933461bf897344c1f21d9746f9a4eab94156042bb9cbb62660' 
  AND token = 'ZhNUGIiLU9BgMLapmoKrByL8fIOu2DHWuuPoJXLz/LM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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