SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66cfb1170b652ae66644a0afe55435ab28f9fe1694dc120f6f363dc856ebbc64' 
  AND token = 'GrFj+C+t+Y7mqgOLbh+tt8stQOs7pOdcWQ2TEUzPYsM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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