SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c3c62faf7dbd3024117ee81d476e7b8958bffce53f7a4505da6568d54fba280' 
  AND token = 'X58+z9SewEvPnfjHyp2p2a2NWCr2uL6Oh+PqkypE6zQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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