SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a90e6c384afcf2c170e145895de60b06a6a6514edba563b38c4ca2eeb61f839' 
  AND token = 'z9aspLFOxiccT3o9+0VR6W/4yuNtE97CqJMDWyJ49Bw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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