SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df27474cce52fd88cf39634a3848ab8ae132e5baf2cdf728ac58190160f50d71' 
  AND token = '3RCtIWxlKEp0Lyj2dxSEXbWX+mQqOxIaIu4qxUUXUj8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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