SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8979433465928a108948b66e5b5c1b6047a777a9c575430746c191b112567cb' 
  AND token = 'zS0Jwhx7iRLqWTuOmHBbgfUrNE8bI1AgD/SIN/gIZGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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