SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26ad3931c75082c05e7d44106730e04e0902f1257c48d0e19571224811ff773b' 
  AND token = 'jyV9O/GxhzUTSpf/nOYqwxA+yw+JQ+FhNg/Nz8sEfkg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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