SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2524d8d30c7a7a5b6cec2275b330c3c86447a821fdfcbaa85572f51e6da2c270' 
  AND token = 'LgYyhx2b1/Ag2NZfyKW2zPKmyxNo/WdOXiOHklXX9rY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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