SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '592c17af99d0f2a193ecdd4da2d0ded4e864d12946fee0e57b9bbcd08c917216' 
  AND token = 'zPnwRw8ipkg3p1if+GNJ9aBF4Gg264HcZ2PK3YMWv3w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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