SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ffcfbe1a850447fe06643894454ef8dcd08386a70a54db21e9c621288994dbc' 
  AND token = 'y9e7md7aJXjwpuIjxMDKcXRux50biE8tKWQrYafuv4I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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