SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '446c1f59cf2795ea2e324246d6e7def2bcab219ee6447ef3a42dff31ce7ca3a9' 
  AND token = 'sCUySkh8vrotgF7gUuc8vIrBTAPCk6aLwyszcg0u4Kc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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