SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '415de86fe73c62c0609e3b0539358ae2cc87c4d33a1ba84748d9b766615c3d87' 
  AND token = 'Ra4tMGBRou7wD8IV4tfpZk3k0DEB4nTVYVtvClDLaEI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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