SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a63e9285af1e6c583753c759f9219c9e9b7b249efa5038a06f5bba5c18d4154' 
  AND token = 'V8qzHAR/hwzRK5pJiuIZ4+tdz3lpip7aytg+cJKq4Yo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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