SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37cb233eff668aedfbbb87b4470f7cade6d7939a81ebec31fb623cc05c04cbbb' 
  AND token = 'kWag7A5vex7XQ63QH6AONOBPL6XFWvEBuZlbOza4Y38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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