SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82835114288d55b49ef7f0dc2d88a23af309385f3ab1d711431deb87d04e4dfa' 
  AND token = 'KVB2rsqSiHFZuEtJKwpSrJUfdJMCWGlZzluAM5Ubakk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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