SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3051123985b730f71d0e543184954d3a02f661afed46bba4b9e0f1f12b372263' 
  AND token = 'SZATupu/Dg6cJGNrSUv+HoRBD9Xea0avRWL9RAgE1K8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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