SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cceed0891a8a2a7efecdbe9befbb4370056b06a064ca7282dd5c3b268a5e5fd' 
  AND token = 'D+f37hMxNNe7ulI5UhROsTmVmgnGrfMDElzde6WEAQA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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