SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83bbf892d67c2f61902731a9bbc7ce635b5c0e083da4e975e42756b0353ccdf8' 
  AND token = 'HUvZrUCL0gBQ2F72pPnSvFSadEhYw/NuY99Evujlaow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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