SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c0b97338793bc0eacb0d1129a057c392210e616cc72a733d766ca3f3f0ea18d' 
  AND token = 'jSUrRomlsVAg39CjYfoRYOiCUnWurrrQ89Hz5bteuWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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