SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45d741c309cfc9f93c85507f80ef6b1f952bcd301dd8858c7df29ba6b56be4da' 
  AND token = 'TIHR84TWoC+OfPAyQiI4+jpqnPF83Hr6+BPUPaKNxYc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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