SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1b4331b69f6f278b9fd52f5dc2c6e47ea24316ab7e9caaf8c0276742d8d68e7' 
  AND token = 'Cqud/hHGRwRzgprp/i39Xs96EmED0Kmk/rPHyzI5UyY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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