SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb52dcd42ea7db9806053ae69b843cd5478e8005ce18cd4bd3f8b810692b56af' 
  AND token = 'yEWCf8OV0aRzzq+ERZ9moikLkIHZxmW+j4194psZcjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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