SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10bc7bc7138c9ba1d6f991da27de8f3d3372784e9eee2425bf8ee570dac997c4' 
  AND token = 'WZlYcJP6aj8P+zVn/eMvDVgRpcoJjgPrJevtnFCZO+M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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