SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f7d6e73940c5d6bca4ea7153aa8352f78e2f1c8f90b9eedb4a8363a3baf7982' 
  AND token = 'jyFiTFW3QUyqZPnJg322pFf+cLjnilvdXizpb+uzzpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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