SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '355172e4b8f0ec0face3d36b09330bfd57977be898cada65aa0e2639fb05ab46' 
  AND token = 'hNfSugVvy/HrIsKLGlaB9ACUHijHyy8GXuIz+e9+i1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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