SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b9e301bd94c55bab741084073f3c8f2a2bd46df8cf8d1803cce037188f541c2' 
  AND token = 'JpLHXBX7oRyHAIPQuh+RCeDQXdNRmI1U9kkFm/mNRMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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