SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87491387aeb9eb9ad15404d2f0ffe0024a65205d99b490e86e13a23380ac95e7' 
  AND token = 'Vkc3fCFz5fVTcaz0yWFGj66+HrRTtnHGo/3VBBKMSQ4=' 
  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"
    }
  }
}