SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b99627b33a7f364edda4b3287993baa8b2294b4ef8242ab2ceeacf8203df343f' 
  AND token = 'oz0E5sCXWYRSU0yLc9MXAHXY+mtHO1hgpN+aZE8oDVI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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