SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '370b477ae54b4d96807dff13525d125c9c28bb7a7bc3cee6fb8f6412e5b97159' 
  AND token = 'cfincs8YSx+WloCmLu0Ihp5dqfJQpcmpBC3+CjSKXHA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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