SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3a6b83bee787733ac56a0bc31899615613ff8e947bfff47f9c38848317c7807' 
  AND token = '9VNjJtJa8pHGiXhOhHrYT/tGPI3+lsvGF9hxt+d5MGk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}