SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3de42493667cb3f5a71d89333ce2f1df18893619752df93d210f88c46d934825' 
  AND token = 'tMdEQDrYpbNIrBu5viB7lhYXpfm+z+BXALG0VIbeJoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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