SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6b3f86c6d293a4fb28c3eb4b09b6cfce02710baa25fd8e2a54e785973082d4f' 
  AND token = 'DdbklVY0LBW/O9cYo/MBorr7LBVkLF8FueyYvnIOoOk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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