SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffd54a93f31dac07513a41972c9992a9b82a6203ef20e3cb165a615009a548ca' 
  AND token = 'CbPgB/44BrgbgWgP7bZtREQmRYNf5zxLlLVsHZGqHR4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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