SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '159d03d48615a1fa831a9fa8d763651d678671af2b19d076918a91853d1dab3d' 
  AND token = 'I6HSDwbGUy+UzB+E8f7yTqPK8LWTo8OKsCJ/2E+/KAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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