SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e1320dfd517e84b4e4930bec41651fff7e3992fe196ed85b792776a44203da1' 
  AND token = 'pc76P+zMqoBUzcYoautbYSLLui8sI9ZRaLA2aibM5Ro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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