SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71b1045283e119bdfce4117345a97d36e19bd49f43908afa46b68db30f97e86a' 
  AND token = '8rh1UCQZGSb4v0/h/YKGbdcYI2/w6nF1L1HlqofOr+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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