SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd66bbb6968b3727ecf7521ab26eb5675bfee99eb8903af8a733d927a78d4f8fd' 
  AND token = 'Pn4idX8r1DIfU7jWBQRvAcYF8T+WyCZe7YSFMgLoDQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}