SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19683f8d6c31596405ee30330998486c2292b56c67aa6c560afe424330615c35' 
  AND token = 'kNG6rEo22tWoaEOtV8Whq2OfgmANgS2D7NPBME+1X9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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