SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3210b8c746e13a8fcb135079beffbbc99a522d96fe0826a4d10aa4801814b44' 
  AND token = 'YGUiHb5+CfbXnyygaEpXiAaN/gXQJi6me5i8YKvg2Z4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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