SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6a2e967f3019d7f46dba0ae5def10fa64271ce78ba09fd0b6781912167f987f' 
  AND token = 'BlkAmEsuNFsnlxyDNgWtIagZkN0qrTErt9ofAWC3dZ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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