SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8bbac0e0e1907db8feb3025d312b1e377b90dd3ed45bc87bb0677ac9ba12882' 
  AND token = 'PlXCIDcbqJ73qfX1eTq15YiQVcSAVbmjjrAyeIESYKQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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