SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a20b790df2dc61f4db4a355f613de3927e66dbc2ee40b7158977975714bfbe6' 
  AND token = 'OGSQuAd5AUU3OdjkkMobB+vAuuMhv4d8xhIqF9KmLDw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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