SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f789e6d808af3a1e1416bc6a17e21ab3ff2ba014c25dce4e3d4b53b32cb13850' 
  AND token = '/3Wwunr8BptjU1WL7CfgHZpJzKDykg6gSpeO2qQFb9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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