SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f3d3d41c79309e2a948ccf2972eae936830c8edf20accf9ae667ae573932a9b' 
  AND token = 'iXE6tj94SOQVEll+QKvePxeFywxrweMpsy6Qlbi9SCQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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