SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98f9d0fabbab40b9688305c6cbfe233cd2009d35afdce838e184741fced3dac7' 
  AND token = 'LzZxG7w1wO2AvGm99tpMYbeel9qm7xDBSUkgunE+Yug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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