SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5332b9c383290072da11ff6f434116afa33ac2693df74411602438442e85e3c6' 
  AND token = 'qiB2ooVQ+KvqsSlIDhkjeZNRRmJV3YYd5M6PXhVgqVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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