SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e77c8172ad416cdea69efcbaf293bc817987b9af26f9dab8ae3ed9c1f522e49' 
  AND token = 'h7HfROuLWyMT0SIKNwFs5xiSrcMU4eoaBtwgWz2pORU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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