SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3753f731543eebf455204d8daa8744f3f144e9cba2fed06dc9920e336b32830b' 
  AND token = 'zHHZ2w5iuFodHGzm+J7p+gGvv0/T11axkoGgQatEsgI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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