SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b714590fadfc8576e2b373ed2dd17995dd38f18ccc56228a64fdfae7f836191' 
  AND token = 'AEJB57ISHH8+zrokkYOzwkXmhWafAdt9HmgMLlcFo5U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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