SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '615a27d9ba629a0e7fe04405519bd73d14892035003b3a3249f8460c3a203b1c' 
  AND token = 'haVP+ZBAlpUdpED9g0QNHCNuYrtq1ObhAkctuXiVLWM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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