SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c58263cf7213f4bc41c344b5fc3df83925d2d70e40812c67b113cdadfa7068a0' 
  AND token = '+510wH5o+XYaFEMK9V+/qElHvaW4R1VozGwyCQ0f7pg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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