SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6fc910e0cf12f6ce8e8602e8dee9e8e70dbe8abbdd74eff29566f3d31b11314' 
  AND token = '1RXw/GjKobYoPTjtfSK0fCBinIBJ2K5bWYlHWmvObY0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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