SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe38a6f9b951e5320024d138d8ce39a334fcdc7484d415252384dc0a6b1db19b' 
  AND token = 'wEnoNzwzQHcKuDZS+Yff5875B2BYxbO38FWY26a1rBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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