SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '95ad1e9bc7b879a53c66b4388f61e8d20bd2515e9fb10e3b3521f7cece9d8f5a' 
  AND token = 'QgsGvGr+vGBQqpfBov3fJlWoYHv9gUpEPmi4H3ygpxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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