SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26f3477d80b4613e10209084a7ff0d809e54bfcdc3a294edd50f35a7782b7551' 
  AND token = '/FFwuIcUTj4YHf/nVLHpW+vpjR8x2RaHplsAaIYibg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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