SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a70576e0e21ddde552fe900eb66165759f04af721a4a3075b1a9398e3472da5' 
  AND token = 'FPhB+7/uqJHWwZkW1ulpbua2EuoKuN8apL5/SefHfqA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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