SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '073ffb0178ce5e34b50acce940c15893e4f0c0bfcc54bef20b51b90c566fdb5a' 
  AND token = 'gHQxHvDJJrphq2n3RU0xPl2i62dC6lpIUWR1Y0VmWH8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}