SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c1ae6cadd172b7842f2055c34480f70100ba1a2d1e9a977d3ba3649d099b5fe' 
  AND token = 'mDvrJP82uXsi5GBdZn5ujyUfh3Ms0+zKNTX2kGL+CDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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