SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d1fb16ab5937b3a9f0f587f18727b5c920b605a1911304edca6f6b9e6bc9427' 
  AND token = '/qL6Q/DZqkGzAgmw1aLhxyQ68vtKUgkpGkpcoDVinUs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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