SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fbecf790057706e2cc7208c668e321a238a5c30a3286c98df0a195a5e35d0b5' 
  AND token = '9VhIRabPLslYVJgi0H1VmfJihKBPcGhnMkQfFE5EM0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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