SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fa4738a5437b77a0d141669c94305aab5c423d7582e024ee89674fb90695d3e' 
  AND token = 'CAfJNNim2NUdRSEZIQiAAnYzOmxm0bf0MVe3fKqlzTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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