SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a27adca771e293e4eec2ed259af73cb908930e149dbc8cf4be15b8ab56a68a29' 
  AND token = 'CreEqSdPdBxZh9oeeWxP8OXDweppcbLYURYrhlcb/Bk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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