SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '491d6563cca2efce68f352eb6a180e4d95168a9a68b586f3849f734f1ca485a8' 
  AND token = '6fXY0Vt+zzW0B+gv22T/HO2ZEBE8HGWMhqOs1j+8d9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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